An IC card comprises a central processing unit (CPU) and a memory circuit which are respectively built in a card. That is, the IC card is a kind of computer. Accordingly, the IC card can be applied to a variety of purposes.
To make the IC card generalized, the standardization of the IC card is now under progress internationally according to a standard of an International Organization for Standardization (hereinafter referred to as an ISO) and in Japan according to a standard of a Japanese Industrial Standard (hereinafter referred to as a JIS).
For example, according to ISO7816-1, ISO7816-2 (corresponding to JISX6303), a distance A ranging from an upper end 101 of an IC card 100 to an upper side of ready access terminals 103-1, 103-2 (a side nearest to the upper end 101 among sides defining terminals) of an IC chip module 103 is set to be 19.23 mm in maximum, as illustrated in FIG. 15.
According to an ISO7811-5 (corresponding to JISX6302), a distance B ranging from the upper end 101 of the IC card 100 to a base of a third track 105a of a magnetic stripe 105 is prescribed to be 15.32 mm at minimum, and 15.82 mm at maximum as illustrated in FIG. 16.
FIG. 17 is an enlarged cross-sectional view of a main portion of the IC card provided with a magnetic stripe which meets the standard as set forth above (which is a so-called JIS-I type IC card in Japan). A positional relation between the IC chip module 103 and the magnetic stripe 105 can be easily understood from FIG. 17.
In this case, a distance C ranging from the upper end 101 of the IC card to a base of the magnetic stripe 105 comes to 16.82 mm which is the sum of the distance B ranging from the upper end 101 to the base of the third track 105a, i.e. 15.82 mm in maximum and a 1 mm margin for covering errors. Since the distance A ranging from the upper end 101 to the upper sides of the ready access terminals 103-1,103-2 is 19.23 mm in maximum, a distance D ranging from the upper end 101 to the upper side of the IC chip module 103 comes to 18.23 mm which is the difference between the distance A and a 1 mm margin to be involved in manufacturing the module.
Accordingly, a gap E (=D-C), i.e. between the base of the magnetic stripe 105 and the upper side of the IC chip module 103 comes to 1.41 mm.
If stress is applied to the IC card to bend the IC card in a direction of a short side thereof as illustrated in FIG. 18, the stress is concentrated to the portion adjacent to the gap E, particularly to the portion adjacent to the upper side of the IC chip module 103 since deformation in thickness of the card substrate is sharp at the portion adjacent to the gap E.
It is an object of the invention to provide an IC card capable of relaxing stress and enhancing durability compared with the prior art IC card.